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Micro Word Clock v2
Description
A tiny replica of the famous Word Clock, using only an ATmega microcontroller, a DS1307 Real Time Clock and a few passive components to display the time on an 8x8 LED matrix. The letters have been printed onto a transparent sheet and glued over the LEDs to produce a readable time. See the YouTube video here.
Directory structure
- MicroWordClock2-Arduino contains the firmware, including pin definitions for the LED matrix and location of the words in each language.
- EAGLE contains the schematic and PCB design files for the proejct.
- Graphics contains the design for the transparency sheet to place over the LED matrix to form the words, designed in Inkscape. Contributions in more languages are welcome!
Bill of Materials
| Part name | Package size | Reichelt part number | |
|---|---|---|---|
| IC1 | ATmega328P-AU | TQFP-32 | ATMEGA 328P-AU |
| IC2 | DS1307Z+ | SO-8 | DS 1307Z |
| C1 | 220nF ceramic | 2012 metric / 0805 imperial | X7R-G0805 0,22µ |
| C2 | 2.2uF tantalum | 3528 metric / B-case | SMD TAN.2,2/20 |
| S1 | SMD push button | 6.2x6.5mm | TASTER 9314 |
| XTAL | 32.768 kHz crystal | 3216 metric / 1206 imperial | 32,768 CC7V-12,5 |
| LED matrix | 8x8 matrix | 20x20mm | GYXM-788ASR* (DealExtreme) |
| PCB | 20x20mm | OshPark | |
| * Probably any LED matrix labeled 788 should work. |
You will require an In-System Programmer (ISP) to write the firmware onto the microcontroller.
Burning the bootloader and uploading the sketch
Please read these two tutorials if you are unfamiliar with burning a bootloader:
The required procedure is the one described as "AVR on a breadboard" and "Minimal circuit", respectively, as there is no external crystal attached to the microcontroller.
Please download Carlos Rodrigues' Barebones ATmega Chips board configuration file: https://github.com/carlosefr/atmega (instructions inside)
The ICSP header on the Micro Word Clock PCB is the standard layout described here (Fig. 2).
Contributions
Carl Monk has built his own version using a Unicorn HAT.
quistoph has made a Dutch layout.
Tanguy Rewers independently came up with an alternative Dutch layout (labeled as dutch2).
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License
This project (both software and hardware) is published under a Creative Commons BY-SA 3.0 License.